Welding hardenable steels



, Patented 1312,1939 I v I Y o UNITED STATES PATENT. OFFICE I mnz lfaiiimfefifliifidzzfmny,

assignor to Gebr. Bohier & Co. Aktiengesell schaft Wien, Vienna, GermanyNo Drawing. Application March 19,.193'1, Serial No. 131,859. In GermanyApril 1, 1935 8 Claims. (Cl. 219-8) This invention relates to weldingrods, and Steels, second edition,'edited by E. E. Thum andmorespeciflcally to a new and useful welding rod published by TheAmerican Society for Testing for forming strong fusion-deposited weldsin ar- Metals. Although the phase diagrams have not ticles comprisingcontiguous members of harden been determined for some of these complexauso able ferritic steel. v tenitic steels, simple trial will suflice'to deter- Hardenable steel is a very dimcult material to mine the .exactcomposition required to meet the v weld by fusion-deposition methods,because the conditions disclosed above, heating conditions of weldingcause stresses Although the known phase diagrams men- -which embrittle,weaken, and frequently crack, tioned above would indicate thatldilutioneffects the hardenable steel. --An object of this invenoccurring duringwelding would produce a brittle tion is :to provide strong and ductilewelds in martensite or austenite-mar ensite structure at hardenablesteel, and to provide a method and :j .the transition zone, I have ound,surprisingly. a welding rod for producing such welds. This that astrong, non-brittle austenitic or austeniticobject is attained,according to the invention, by ferric structure is obtained, and it ischiefly to the use of a welding rod composed of certain this fact that Iattribute the valuable benefits 15 '85 ment in welding rod, a strong andductile joint 2% greater than that required to make the steel austeniticsteels. attained according to the invention.

I It would be expected that austenitic steels I claim? would not besuitable for welding hardenable 1. Austenitic steel welding rod forfusionsteels, because dilution efiects at the transition depositionwelding hard'enabie ferritic steel mem layer between the austeniticfiller material and bersby a weld substantially free from martensite thepearlitic or other ferritic-type base material. containing carbon in anamount not exceeding would be expected to form a brittle martensitic0.4% and containing at least one metal of the material. I have found,however, that by using. group consisting of nickel and manganese, the anexcess of austenite-stabilizing alloying elesumof the nickel andmanganese being atleast may successfully be made. completely austenitic.

I have further found that an excess of at least 2. Austenitic steelwelding rod for fusion- 2%, and preferably at least 4%, of nickel ordeposition welding hardenable'ferritic steel memmanganese, or both, overthe amount required bers by a weld substantially free from martensite toproduce a permanently austenitic structure containing carbon in anamount not exceeding 3 under n ordinary rates ofcooling encountered 0.2%and containing at least one metal of the in welding practice, isrequired to attain the group consisting of nickel and manganese, theobjects of the invention. sum of the nickel and manganese being at leastThe minimum amounts of the austenite-stabil- 4% greater than thatrequired to make the steel 85 izing elements required depend, of course,upon completely austenitic. 3 the amounts of carbon and other elementspres- Y 3. Austenitic steel welding rod for fusionent. The minimumamounts may readily be dedeposition weldinghardenable ierritic steelmemtermined, however, by consulting the known bers by a weldsubstantially free from martensite phase diagrams, such as those shownon pages containing 2% to I hromium, carbon in an 40 68, 85, and 116OFEdeIstlihIe", second edition, by amount not exceeding {0.2% andcontaining at m I. Rapatz, and on pages 722 and 751 of "The Makleast onemetal of the group consisting of nickel ing, Shaping, and Treating ofSteel, fourth ediand manganese, the sum oi. thenickel and mantion, by J.M. Camp and C. B. Francis. ganese being at least 4% greater than thatre- I prefer to use steels-containing no more than quired to make thesteel completely austenitic. 0.4% carbon, and the very best resultsareusually 4. Austenitic steel welding rod for fusioni attained whenthecarbon content does not exdeposition welding hardenable ferritic steelmemceed 0.2%. I also prefer to use steels containing bers by a weldsubstantially free from martensite from 2% to 35% chromium, the range of16% containing 16% to 30% chromium, carbon in'an to 30% being especiallyuseful. Further, amount not exceeding 0.2% and. containing at althoughthe austenitic chromium-nickel steels least one metal of the groupconsisting of nickel 60 may beused, I prefer to use the chromiumandmanganese. thesum of the nickel and manm'anganese,chromium-manganese-copper, chroganese being at least 4% greater thanthat'remium-manganese-nickel, and chromium-mangaquired to make the steelcompletely austenitic. nese-nickel-copper steels described, forinstances, 5. Article comprising at least two contiguous .ll on'pages497 to 501 of The Book of Stainless membersof hardenable f'erritic steelunited by a fusion-deposited weld composed of 'austenitic steelcontaining carbon in an amount not exceeding 0.4% and containing atleast one metal of the group consisting of nickel and manganese,

the sum of the nickel and manganese being at least 2% greater than thatrequired to make the steel completely austenitic; said weld and thetransition zone between the weld and the said members beingsubstantially free from martensite.

6. Article comprising at least two contiguous members of hardenableferritic steel united by a fusion-deposited weld composed of austenirtic7. Article comprising at least two contiguous members of hardenableferritic steel united by a fusion-deposited weld composed oi austeniticsteel containing 2% to 35% chromium, carbon in an amount not exceeding0.2% and containing at least one metal of the group consisting of nickeland manganese, the sum or the nickel and manganese being at least 4%greater than that required to make the steel completely austenitic; saidweld and the transition zone between the weld and the said members beingsubstantially free from martensite. 1

8. Article comprising at least two contiguous members of hardenablei'erritic steelunited by a fusion-deposited weld composed oi .austeniticsteel containing 16% to 30% chromium, carbon in an amount not exceeding0.2% and containing at least one metal of the group consisting of nickeland manganese, the sum or the nickel and manganese being at least 4%greater than that required to make the steel completely austenitic; saidweld and the transition zone between the weld and the said members beingsubstantially free from martensite.

FRANZ BAPATZ.

